Yang Kai, Fu Qidong, Prates Henrique C, Wang Peng, Kartashov Yaroslav V, Konotop Vladimir V, Ye Fangwei
State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Departamento de Física and Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa 1749-016, Portugal.
Proc Natl Acad Sci U S A. 2024 Nov 19;121(47):e2411793121. doi: 10.1073/pnas.2411793121. Epub 2024 Nov 15.
Topological transport is determined by global properties of physical media where it occurs and is characterized by quantized amounts of adiabatically transported quantities. Discovered for periodic potential, it was also explored in disordered and discrete quasiperiodic systems. Here, we report on experimental observation of pumping of a light beam in a genuinely continuous incommensurate photorefractive quasicrystal emulated by its periodic approximants. We observe a universal character of the transport which is determined by the ratio between periods of the constitutive sublattices, by the sliding angle between them, and by Chern numbers of the excited bands (in the time-coordinate space) of the approximant, for which pumping is adiabatic. This reveals that the properties of quasiperiodic systems determining the topological transport are tightly related to those of their periodic approximants and can be observed and studied in a large variety of physical systems. Our results suggest that the links between quasiperiodic systems and their periodic approximants go beyond the pure mathematical relations: They manifest themselves in physical phenomena which can be explored experimentally.
拓扑输运由其发生的物理介质的全局性质决定，并以绝热输运量的量子化数量为特征。它首先在周期性势场中被发现，随后也在无序和离散准周期系统中得到研究。在此，我们报告了在由其周期近似体模拟的真正连续的非 commensurate 光折变准晶体中光束泵浦的实验观测结果。我们观察到输运具有普遍性，它由组成子晶格的周期之比、它们之间的滑动角以及近似体（对于泵浦而言是绝热的）的激发带（在时间坐标空间中）的陈数决定。这表明决定拓扑输运的准周期系统的性质与其周期近似体的性质紧密相关，并且可以在多种物理系统中进行观测和研究。我们的结果表明，准周期系统与其周期近似体之间的联系超越了纯粹的数学关系：它们体现在可以通过实验探索的物理现象中。
